The present invention relates to a reclining seat apparatus, and in particular to a reclining seat apparatus in which the reclining angle is set to be adjusted by a motor.
In general, a reclining seat apparatus has a seat cushion which is provided at its rearward side portions with a pair of lower arms respectively, and a seat back which is provided at its lower end portions with a pair of upper arms respectively which are corresponding to the pair of lower arms. Each lower arm is provided therein with an inward gear which is in mesh engagement with an outward gear of each upper arm which is eccentrically arranged to the inner gear. Due to the difference between the outward gear and the inward gear in number of teeth, when the outward gear is rotated by a motor, the lower arms are rotated, which results in that an angle defined between the seat cushion and the seat back is adjusted according to the rotation thereof. When the seat back reaches its frontmost position (rearmost position), the rotating lower arm is set to turn on a first limit switch (a second limit switch), thereby turning off the motor. The foregoing structure is disclosed in the shop manual for "DIAMANTE" published by Mitsubishi Motor Co., Ltd. in May, 1990.
However, in the foregoing structure, if one of the limit switches malfunctions due to an unexpected accident or other reason, the relatively large torque is being applied to the outward gear continually until the motor is turned off manually. In light of the fact that such torque application will cause the separation of the inward gear from the outward gear, both of the upper arms and the lower arms need to be reinforced if the prevention of such separation is desired. Such requirement is contrary to recent requirements for lighter weight automotive vehicle parts.